Why do I get more search results when I add more keywords?

When I search in dw Answers, the more keywords I use in my search the more results I get. I expected that adding more search words would help refine the search rather than causing it to include more choices to search through. How can I narrow down the choices that I have to look through when searching in dw Answers?

It behaves like an OR vs an AND. I suspect that most folks will think it should be like an AND, so the more keywords you use (or the more specific you are), the fewer results you should get. I find the way it is working now to be a bit confusing...

Referring back to the example used in other comments in this thread, using the the syntax +bpm +monitor = 24 results. So this syntax does work to narrow the results. I also did a couple of quick tests to use the same syntax to search on words that were not tags and it did appear to work similarly for those search words as well. For example, searching on bpm = 334 results; maximal (which is not a tag) = 14 results; +bpm +maximal = 3 results.

I searched with +[bpm] +[uca] today and it returned questions that do not have the uca tag associated with them. Is this an expected behavior? What should I do if I only want to retrieve questions that are tagged with with bpm and uca? Thanks much!

Keep in mind, putting the brackets [ ] around the tags is the only way to differentiate between a tag and a search term when entering the terms in the search box. And, you can't just search on the tags without a search term (without using the dWAnswers drop down, a tag in the search results, or a URL).

I wanted to know how this works so I did some test searches and these are the results:

1) search on "cics + cicsts wait" -- 424 results are returned -- thankfully it looks like the top results are the ones I want

2) search on "cics cicsts wait fccfqr" -- 425 results are returned

3) search on the 2 tags "[cics] + [cicsts]" -- 0 results are returned because a search term is required

4) search on "[cics] + [cicsts] wait" -- 9 results are returned which is the number of CICS items with wait

5) search on "[cics] + [cicsts] wait fccfqr" -- 9 results are still returned so adding "fccfqr" doesn't help narrow the search

6) search on "[cics] + [cicsts] wait +fccfqr" -- 1 result is returned so adding "+fccfqr" without a space

7) search on "fccfqr" by itself -- 1 result is returned

So, when using dWAnswers, it appears that more terms will return more results because it seems to be OR'ing the search terms. But, you can add the [tags] and it will only return posts for the tag(s). And, you can add a + sign (without a space) before a search term to limit the results to items with the search term.

The "Seach tips" under the search box are somewhat helpful but I wish it was working more like Google and other search engines and narrowing the search when additional keywords are added. I think that's what most people would expect.

At some point, in the past few weeks, I think the search engine changed the rules again. So using an example used before.

Search for BPM = 514 results

Search for Monitor = 440 results

Search for +BPM +Monitor = 915 results.

Search for +[BPM] = 464 results

Search for +[Monitor] = 67 results

Search for +[BPM] +[Monitor] = 512 results.

My original intent in asking this question was to find out how to search for terms that may or may not be tags. Given these latest results, I am just really confused about what I am getting and how to do a seemingly very simple 'AND' type search.